Stretchable transparent dielectric heaters enable conformal heating for wearables and outdoor applications. However, hydrogel-electrode devices degrade rapidly under environmental stresses. Here, we introduce nonvolatile ionogel electrodes covalently integrated with a poly(vinyl chloride) gel dielectric to eliminate interfacial delamination. The ionogel exhibits 13 mS cm-1 ionic conductivity, 187% stretchability, and transmittance above 90%. The heater reaches 98.6 oC at 400 V with a heating rate of 1.56 oC s-1, 14 times faster than a hydrogel-electrode dielectric heater. At 100 V, the heater reaches 45 oC for wearable applications, representing an 80% reduction in operating voltage relative to a hydrogel-electrode dielectric heater. Also, stable operation is maintained across 4-80 oC, 10-60% relative humidity, and drying-swelling cycles for at least 12 hours. Demonstrations in wearable thermoregulation, transparent defrosting, and smart greenhouse control validate practical viability.